Watch This When You're High - How Do Animals Hibernate?

I'm headed to Colorado tomorrow for the week for a company retreat and some skiing. I can't fucking wait. I was discussing with somebody last night and they told me to watch out for bears. I thought about it for a second and thought to myself, "don't bears hibernate in the winter?"

Then my brain started thinking about what the hell hibernation is. How does it work? How do animals just automatically do it? How don't they eat? How don't they go to the bathroom? It's crazy when you think about it. 

Keep the suggestions coming. Keep them classy. No butt stuff.